Edit comment LC-2108 for Efficient Extensible Interchange Working Group

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Comment LC-2108

Comment Shortname:

Commenter: <pub@upokecenter.com>

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Section of the document concerned:

[Free text description]Document as a wholeEfficient XML Interchange (EXI) Format 1.0 /**/ code... Efficient XML Interchange (EXI) Format 1.0 W3C Working Draft 28 July 2008 Abstract Status of this Document Table of Contents Appendices 1. Introduction [Definition:]   [Definition:]   [Definition:]   1.1 History and Design 1.2 Notational Conventions and Terminology [Definition:]   2. Design Principles 3. Basic Concepts 4. EXI Streams [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   4. EXI Streams [Definition:]  An EXI stream is an EXI heade... 4. EXI Streams [Definition:]  An EXI stream is an EXI heade... name prefix local-element-ns public qname system text uri value 5. EXI Header [Definition:]   5.1 EXI Cookie [Definition:]   5.2 Distinguishing Bits [Definition:]   5.3 EXI Format Version [Definition:]   Example 5-1. EXI Format Version Examples 5.4 EXI Options [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   [Definition:]   6. Encoding EXI Streams [Definition:]   6.1 Determining Event Codes Example 6-1. Example productions with event codes 6.2 Representing Event Codes Example 6-2. Example event code encoding 6.3 Fidelity Options Preserve.prefixes Preserve.lexicalValues 7. Representing Event Content [Definition:]   7. Representing Event Content The content of each event in... 7. Representing Event Content The content of each event in... 7.1 Built-in EXI Datatype Representations 7.1.1 Binary 7.1.2 Boolean 7.1.3 Decimal 7.1.4 Float 7.1.5 Integer 7.1.6 Unsigned Integer Example 7-1. Example algorithm for decoding an Unsigned Inte... 7.1.7 QName 7.1.8 Date-Time 7.1.9 n-bit Unsigned Integer 7.1.10 String 7.1.10.1 Restricted Character Sets 7.1.11 List 7.2 Enumerations 7.3 String Table 7.3.1 String Table Partitions [Definition:]   7.3.2 Partitions Optimized for Frequent use of Compact Identifiers 7.3.3 Partitions Optimized for Frequent use of String Literals 7.4 Datatype Representation Map [Definition:]   Example 7-2. datatypeRepresentationMap indicating all Decima... Example 7-3. datatypeRepresentationMap illustrating a user-d... 8. EXI Grammars 8.1 Grammar Notation 8.1.1 Fixed Event Codes Example 8-1. Example productions with fixed event codes 8.1.2 Variable Event Codes Example 8-2. Example productions that use macro non-terminal... Example 8-3. Example non-terminal macros and its productions... Example 8-4. Expanded productions equivalent to the producti... 8.2 Grammar Event Codes Example 8-5. Example productions with event codes 8.3 Pruning Unneeded Productions Example 8-6. Example productions with full fidelity Example 8-7. Example productions after pruning 8.4 Built-in XML Grammars 8.4.1 Built-in Document Grammar 8.4.2 Built-in Fragment Grammar 8.4.3 Built-in Element Grammar [Definition:]   8.5 Schema-informed Grammars 8.5.1 Schema-informed Document Grammar 8.5.2 Schema-informed Fragment Grammar 8.5.3 Schema-informed Element Fragment Grammar 8.5.4 Schema-informed Element and Type Grammars [Definition:]   [Definition:]   8.5.4.1 EXI Proto-Grammars 8.5.4.1.1 Grammar Concatenation Operator 8.5.4.1.2 Element Grammars 8.5.4.1.3 Type Grammars 8.5.4.1.3.1 SimpleType Grammars 8.5.4.1.3.2 Complex Type Grammars 8.5.4.1.3.3 Complex Ur-Type Grammar 8.5.4.1.4 Attribute Uses 8.5.4.1.5 Particles 8.5.4.1.6 Element Terms 8.5.4.1.7 Wildcard Terms 8.5.4.1.8 Model Group Terms 8.5.4.1.8.1 Sequence Model Groups 8.5.4.1.8.2 Choice Model Groups 8.5.4.1.8.3 All Model Groups 8.5.4.2 EXI Normalized Grammars 8.5.4.2.1 Eliminating Productions with no Terminal Symbol 8.5.4.2.2 Eliminating Duplicate Terminal Symbols 8.5.4.3 Event Code Assignment 8.5.4.4 Undeclared Productions 8.5.4.4.1 Adding Productions when Strict is False Like an element, an attribute may occur in a schema-invalid... 8.5.4.4.2 Adding Productions when Strict is True 9. EXI Compression 9.1 Blocks 9.2 Channels 9.2.1 Structure Channel 9.2.2 Value Channels 9.3 Compressed Streams 10. Conformance 10.1 EXI Stream Conformance [Definition:]   [Definition:]   [Definition:]   10.2 EXI Processor Conformance A References A.1 Normative References IETF RFC 1951 IETF RFC 2119 ISO/IEC 10646 Unicode Database XML 1.0 XML Information Set XML Schema Structures XML Schema Datatypes A.2 Other References Efficient XML EXI Measurements Note EXI Primer EXI Evaluation Greibach Normal Form Huffman Coding ISO/IEC 19757-2:2003 SOAP 1.2 XBC Measurement Methodologies XBC Use Cases XBC Properties B Infoset Mapping B.1 Document Information Item B.2 Element Information Items B.3 Attribute Information Item B.4 Processing Instruction Information Item B.5 Unexpanded Entity Reference Information item B.6 Character Information item B.7 Comment Information item B.8 Document Type Declaration Information item B.9 Unparsed Entity Information Item B.10 Notation Information Item B.11 Namespace Information Item C XML Schema for EXI Options Header D Initial Entries in String Table Partitions D.1 Initial Entries in Uri Partition D.2 Initial Entries in Prefix Partitions D.3 Initial Entries in Local-Name Partitions E Deriving Character Sets from XML Schema Regular Expressions E Deriving Character Sets from XML Schema Regular Expressio... F Example Encoding (Non-Normative) G Schema-informed Grammar Examples (Non-Normative) Example G-1. Example XML Schema fragment G.1 Proto-Grammar Examples   Term_description   Term_description 0 :...   Term_description   Term_description 0 :...   Term_description   Term_description 0 :...   Particle_description   Term_description ...   Particle_quantity   Term_quantity 0 :...   Particle_quantity   Term_quantity 0 :...   Term_sequence   Term_description0 :...   Particle_sequence   Term_description0,0...   Use_sku   Use_sku 0 : AT("sku") Use_...   Use_sku   Use_sku 0 : AT("sku") Use_...   ProtoG_ProductElement   Use_color 0 :...   ProtoG_OrderElement   Term_prod... G.2 Normalized Grammar Examples   NormG_ProductElement Event Code Use_col...   NormG_ProductElement Event Code Use_col... G.3 Complete Grammar Examples   CompleteG_ProductElement Event Code Use...   CompleteG_ProductElement Event Code Use... H Recent Specification Changes (Non-Normative) H.1 Changes from Third Public Working Draft H.2 Changes from Second Public Working Draft H.3 Changes from First Public Working Draft I Acknowledgements (Non-Normative)
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Refinement of the section concerned:

Status:

open proposal pending resolved_yes resolved_no resolved_partial other assigned to Nobody Bournez, Carine Brutzman, Don Cokus, Michael Fernández, Javier D. Heuer, Joerg Käbisch, Sebastian Kamiya, Takuki Kuntschke, Richard Matsukura, Ryuichi McGregor, Don Peintner, Daniel Quin, Liam Shah, Grishma ZERGAOUI, Mohamed

Type: substantive editorial typo question general comment undefined

Resolution status:

Response drafted Resolution implemented Reply sent to commenter

Response status:

No response from Commenter yet Commenter approved disposition Commenter objected to disposition
Commenter's response (URI):

Comment:

I want to make a suggestion on the section 'Deriving Character Sets from XML Schema Regular Expressions':

I want to propose that datatypes with a regular expression containing a "charClassSub" should have no restricted character set. The reason is that all the remaining parts of the regular expression derivation expect only a union of characters, which is very efficient in determining whether the expression contains a restricted character set or not. Having a 'charClassSub' as part of the derivation process may complicate this, as the program now has to subtract portions of the character set as well as add to them, which may be a problem if the character set contains a large number of characters, like this:

[&#x20;-&#xFF00;-[&#x60;-&#xFF00]]

That regular expression above would yield a restricted character set of 64 characters; however the implementation may require storing thousands of characters (a naive implementation, yes) before it must exclude them in the 'charClassSub' portion of the regular expression. Another problem is nested 'charClassSub' sets. For example, the following regular expression is allowed:

[A-Z-[B-Z-[C-Z-[D-Z-[E-Z-[...]]]]]]

Both problems make 'charClassSub' problematic in restricted character set derivation. I thank you for your time.

Related issues: (space separated ids)

WG Notes:

Resolution: We excluded those regular expressions that contain either wildcard (".") or negative character groups, since those expressions tend to result in large set of characters. Even those rare cases that are not the case often have better alternative ways to specify the same effect, such as [^&#x30;-&#x10FFFF;] can be expressed otherwise simply as [&#x00;-&#x02F;]. On the other hand, character class subtraction is retained because, unlike wildcard or negative character groups, the operation always results in a number of characters smaller than that of the 1st operand. We also found that character class subtraction does not add much computational burden if it is properly implemented. Please also note that it is our expectation that schema authors can provide some help by being aware of the general cost of each operation and specifying patterns in ways more friendly to EXI processing.

(Please make sure the resolution is adapted for public consumption)